Superb FX ultrawide, and ultracompact, too. This 20mm f/3.5 is Nikon's smallest and lightest ultrawide except for the slightly smaller 20mm f/4. This is the same size as a 50mm lens.

Not for

I wouldn't bother with this on a DX camera. I'd use any DX lens, like the 18-55mm kit lens, instead. As a manual focus lens, I wouldn't use it for sports, kids or action since it's too hard to track focus by hand.

This was the "cheap"
20mm lens compared to the larger 20mm f/2.8 AI-s back in the 1980s. The
sharpness of this f/3.5 is at least as good, and the tiny size and common
52mm filter size makes it preferable. It has the same sharpness, distortion and falloff as all the
other Nikon fixed 20mm lenses I've evaluated.

The manual-focus Nikon 20mm f/2.8 works great with most Nikon cameras, 35mm and digital.

It works flawlessly with every manual focus Nikon ever made, from the F of 1959 through the FM3a and today's FM-10.

On the D3X, D3s, D3, D700, D300, D200, D2 and F6, use the "Non-CPU Lens Data" menu option to set 20mm and f/3.5 to get full color matrix metering, EXIF data and finder read-out of set aperture. It works great in aperture-preferred as well as manual modes on these cameras.

It works perfectly on every professional 35mm camera (F, F2, F3, F4, F5, F6), and adds Matrix metering on the FA, F4 and F6.

The meters of cheaper digital (D90, D5000 and below) and cheaper film cameras (N80 and below) will not couple (or work at all) with this lens, so you'll be on your own guessing exposure using the rear LCD or an external meter, or get a tiny Gossen Digisix meter and hotshoe adapter to meter manually.

Nikon repackaged their 2.1cm (21mm) f/4 rangefinder lens, originally designed for the Nikon SP, for the F-mount SLRs.

It required the use of mirror lockup and a separate finder slid over the funky rewind crank of the NIkon F, as it poked all the way into the camera.

Nikon made about 5,000 of the 2.1cm f/4 lenses.

1967-1974

The 20mm f/3.5 UD was Nikon's first 20mm lens. It was the ultrawide for the late 1960s and early 1970s. There was no wider non-fisheye lens made by Nikon until the insane 15mm f/5.6 of 1973 and the 18mm f/4 of 1974.

Nikon made about 40,000 of the 20mm f/3.5 UD lenses.

1974-1978

The tiny 20mm f/4 (52mm filters), the smallest ultrawide ever made by Nikon or Canon, replacing the big 20/3.5 UD, with similar optical performance.

Manual focus has the exquisite classic Nikon feel, which is duplicated nowhere else.

One light fingertip is all that's required to focus.

The AI-s version focuses with a smaller turn of the ring, while the AI version here spreads the focus range over a larger area to allow more precise focus, depth-of-field calculation and more precise distance markings.

AI version focus scale markings, 100º rotation

Feet: 10, 5, 3, 2, 1.5, 1.25 and 1 foot.

Meters: ∞, 3, 1.5, 1, 0.7, 0.5, 0.4, 0.35 and 0.3 meters.

AI-s version focus scale markings, 70º rotation

Feet: 5, 3, 2, 1.5, 1.25 and 1 foot.

Meters: ∞, 2, 1, 0.7, 0.5, 0.4, 0.35 and 0.3 meters.

The AI-s version doesn't have the 10 foot or 0.35 meters markings, and replaces the 1.5 and 3 meter markings with a single 2 meter mark.

Ghosts

It has very few ghosts
when pointed into the sun; a hair less than the 20/4 AI.

Distortion is complex on film and FX. It's simple barrel distortion on DX, with no wiggling.

You may as well leave it along on film and FX, since the correction below doesn't do much to eliminate the complex curve.

On DX, it corrects perfectly, but why use this 20mm lens on DX when the 18-55mm AFS kit lens works so much better?

Plug these figures into Photoshop's
lens distortion filter to correct the distortion. These aren't facts or specifications, they are the results of my research that requires hours of data collection and computation.

Like all Nikon multicoated lenses, I've never seen any variation between any of them in color rendition. They all look the same, the hallmark of a well-designed lens line.

Peripheral color balance is cooler than the center, which is typical for ultra-wide lenses of every brand and format. Look at the boring wall above: it's pinker in the middle, and greener in the corners.

Except for this shot of a wall, for which only an idiot photographer would use a 20mm lens instead of a 105mm Micro, I've never seen this effect affect any real photos, like the one at the top of this page. While I also see it on my 75mm Super-Angulon when shooting tests of walls, it never effects real photos.

This effect is an artifact of lens coatings. Coatings work based on interference patterns between various wavelengths (colors) of light and the thickness of the coatings. When light comes at an angle other than 90 degrees normal to the glass surface, the light has to travel through more coating, which moves the effects of the coating to longer (redder) wavelengths.

Think I'm kidding? Look at the reflections in the glass from the front of the 20mm f/3.5, then move the lens to change the angle. I see many green reflections straight-on, which turn to magenta at an angle. This means less green light gets in at the center (since it's reflected more), and more green gets in at the sides. These reflections are less than 1% of the light, but that means that transmission might vary from 100% down to 99%.

I can't see this in real photos. If it bothers you, get the 14-24mm f/2.8 AFS, which has this effect under better, but not complete, control.

Filters,Use with

There is no problem
with vignetting with 52mm filters, so long as you use Nikon brand filters
which have very thin mounts.

The very thick mounts of Tiffen, Heliopan
and B&W filters may cause some vignetting on film and FX digital.

If you, as I, want to use
colors of filters that Nikon does not make, then I suggest getting a huge
filter like a 77mm and using a step-up ring. I use this trick with my
20mm f/2.8 AF and it works fine, even with stacked filters.

The Nikon 20mm f/3.5 is made like they used to. It is built to the highest mechanical standards.

Filter Threads

Metal.

Barrel

Metal.

Focus Ring

Metal, rubber covered.

Aperture Ring

Metal.

Finish

Black enamel over black anodize.

Mount

Dull chromed brass.

Internals

Metal.

Markings

Engraved and filled with paint.

Noises when shaken

Clicking from the diaphragm blades.

Sharpness

Like most lenses, the sharpness of images made with the Nikon 20mm f/3.5 is more a function of the photographer's skill than any limitation of the lens.

On full-frame digital and film, it's soft in the corners wide open, so don't do that if you're shooting test charts. If you are shooting charts, get the 14-24mm f/2.8 AFS, which is superior. I'd never notice any difference between this and any other 20mm lens in real shooting.

Sharpness on a 12 MP FX camera (D3 or D700)

Viewed at 100%, in the center, out to an radius of about 12mm, it's perfectly sharp at every aperture. Diffraction limits sharpness at f/11 and smaller.

In the far sides of the full FX frame (18mm radius), its softer wide open at f/3.5, and becomes s sharpest at f/11.

In the farthest corners (a radius of 21.6mm), It's soft wide-open, and sharpest at f/22.

I'd shot it at f/11 for best results, or simply not worry about it. it works well at every aperture in the conditions you're likely to use it.

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